Air jet nozzle assembly

ABSTRACT

An air jet nozzle assembly having a plurality of nozzles and air plena communicating therewith is provided. Each nozzle has two slots along its entire length which allow for the exit of air from the plenum at high velocity, the slots oriented such that the existing air converges into a single, high-velocity air stream at an angle of from 12* to 20* above the horizontal. The entire nozzle may be pivoted about an axis parallel to the slots. A plurality of nozzles in series are employed in a green boll separator to improve the efficiency of green boll removal from seed cotton.

United States Patent 1191 Laird [4 Oct. 7, 1975 1 1 AIR JET NOZZLE ASSEMBLY [75] Inventor: Joseph W. Laird, Lubbock, Tex.

[73} Assignee: The United States of America as represented by the Secretary of Agriculture, Washington, DC.

22 Filed: June 4,1974

21 Appl. No.: 476,191

3,738,483 6/1973 MacKenzie 209/12 3,759,579 9/1973 Johnston 302/31 FOREIGN PATENTS OR APPLICATIONS 768,878 2/1957 United Kingdom 34/156 Primary ExaminerFrank W. Lutter Assistant Examiner-Ralph J. Hill Attorney, Agent, or Firm-M. Howard Silverstein; Max D. Hensley [57] ABSTRACT An air jet nozzle assembly having a plurality of nozzles and air plena communicating therewith is provided. Each nozzle has two slots along its entire length which allow for the exit of air from the plenum at high veloc- 34/10 ity, the slots oriented such that the existing air converges into a single, high-velocity air stream at an [56] References Clted angle of from 12 to 20 above the horizontal. The en- UNITED STATES PATENTS tire nozzle may be pivoted about an axis parallel to the 2,051,570 8/1936 Norton et al. 209/137 Slots. A plurality of nozzles in series are employed in a 2,139,628 12/1938 Terry 239/569 green boll separator to improve the efficiency of green KlZllOS et al. X removal from eed otton 3,635,336 1/1972 Chapman 209/137 X 3,680,218 8/1972 Belue et a1 302/31 X 9 Claims, 9 Drawing Figures 17 F 3 l E 1 9 l f l U.S. Patent Oct. 7,1975 Sheet 1 of6 3,910,504

FIG/l US. Patent Oct. 7,1975 Sheet 2 of6 3,910,504

US. Patent 0m. 7,1975 Sheet4 of6 3,910,504

SE PAR/ATOR J UNLOADING AIR JET GREEN BOLLS AND TRASH FIGA CONVEYOR US. Patent Oct. 7,1975 Sheet 5 of6 3,910,504

S UPPLY FROM FAN FLAT PLENUM h AIR AIR JETS AIR JET QCONVEYOR FIGS US. Patent Oct. 7,1975 Shest 6 of6 3,910,504

AIR JET NOZZLE ASSEMBLY PRIOR ART AND BACKGROUND OF THE INVENTION Machine-stripped cotton harvested early in the sea'-.

son often contains many green bolls which cause problems during ginning. Cleaning machinery in the gin breaks open many of these bolls, which allows the wet lint and soft seed from the green bolls to become mixed with the mature cotton. This wet material is sticky and tends to adhere to various parts of the cleaning and ginning machinery. It is most troublesome at the gin stand because it sticks to the gin saws and clogs the teeth. Wet sticky material reduces ginning capacity, and in severe cases, completely halts the ginning operation. In these cases, it is necessary to shut down the gin and remove the material from the saw teeth by hand. Cleaning saw teeth is a slow process which results in consid' erable downtime and increases operations costs. Wet, immature lint can also lower the overall quality of the cotton.

Green boll separators presently used at cotton gins are not efficient enough to control this problem, especially in high capacity gins where green boll separators are heavily loaded. Also, the green boll separators require an air intake at the boll outlet throat in order to reclaim seed cotton that was separated with the bolls. This intake of air causes a reduction in suction at the unloading telescope and lowers its capacity. Approximately hp is required to provide the necessary airflow into the green boll separator for efficient reclaiming.

Development of an efficient green boll separator using specially constructed air pipes having a series of air jets to convey seed cotton has been achieved and demonstrated using a pilot model and then a full scale model. During the development of the green boll separator. it was found necessary to design and redesign the nozzle assembly system. This development was accomplished as described in the following narration:

The experimental green boll separator uses specially constructed air pipes having a series of air jets to convey seed cotton. Air is injected into the pipes and discharges through narrow slots to form the series of air jets. The air jets are adjusted to have enough force to convey the seed cotton. but not the heavier green bolls,

which have about 70 percent moisture content. In this way the bolls separate from the seed cotton and fall through the spaces between the pipes. (FIG. 3)

For a given arrangement of air pipes, the capacity and effectiveness of the green boll separator depends upon the velocity of the air jets. At a criticalvelocity, lightweight material becomes fluidized and is easily conveyed. Heavier material, because it requires higher velocities. is not conveyed and separation occurs. If the air velocity is increased further, the separating effect diminshes. The separator also accomplishes some separation as a result of heavy materials hitting the air pi es. losing momentum. and falling from the conveying stream.

A 12-inch \vide experimental model was used to test this principle. These pipes were 2-inches in diameter and were spaced S-inches apart. Each pipe had a 1/16- inch slot across its entire length and a row of /s-inCh holes spaced /2 inch apart. Air entered the ends of the pipes through two plenum chambers, which also served sidewalls for the separator and supports for the pipes. This design of the pipes allowed them to be r0- tated to change the discharge angle of the air jets.

Preliminary trials were conducted in order to adjust the air jets. In these trials, it was found that cotton would not become airborne when dropped directly onto the air pipes. It was necessary to accelerate the cotton to a linear velocity approaching that of the conveying stream before feeding the cotton onto the air pipes. This was accomplished by using a 3-foot section of conveyor immediately ahead of the air pipes to accelerate the cotton to the required velocity. Air jets discharged from the slots at an angle of 85 above the horizontal, and from the holes at an angle of 30 above the horizontal. Air jet velocities of 5000 to 6000 ft/min were selected for further testing.

Two-pound lots of cotton containing immature dried bolls were placed on the accelerating conveyor and fed onto the air jet pipes. (Dried bolls were used because green bolls were not available at the time of the test.) As a check an identical test was conducted using a conventional green boll separator. The experimental green boll separator removed 83 percent of the dried bolls and 1 percent of the seed cotton. The conventional separator removed 40 percent of the dried bolls and none of the seed cotton. These results indicated that modifications should be made to reduce the amount of seed cotton lost by the experimental green boll separator.

It was observed that seed cotton was being lost between the pipes as a result of eddy currents that formed immediately ahead of each pipe. The currents were circulating in a downward direction and carrying some seed cotton under the pipes and out of the conveying stream. To correct this situation, the air pipes were redesigned with an upper and lower slot so that two air jets were emitted from each pipe. (FIG. 2) The two air jets converged at the forward end of the pipe and formed a single, high-velocity air stream. The lower air jet served as a control for the upper jet and prevented downward movement of air currents between the pipes. The pipes were oriented so that the air jets would discharge at an angle of l2.5 above the horizontal.

A test of the new pipe shape was conducted. Air jet velocities of 6900 to 7100 ft/min were selected for this test. Cotton was used that contained very heavy green bolls that had been previously separated from the cotton. The number of green bolls put back into the cotton was such that each 40 pounds of cotton would contain 10 bolls. The new air pipes improved the performance of the pilot model green boll separator. Approximately 98 percent of the green bolls were separated, and there was no loss of seed cotton.

The successful operation of the pilot model prompted the construction of a full-scale, -inch-wide green boll separator that incorporated the new air pipe design. Five air pipes spaced 9-inches apart were used to form a separation section 4 feet long. Air was fed into the ends of the pipes by two plenum chambers similar to the ones used in the pilot model. Slots in the air pipes were 5/64-inch wide and were oriented so that the air jets would discharge at an angle of 12 above the horizontal. An accelerating section containing a rotating beater cylinder and a 15-inch long air-jet conveyor was constructed. The cylinder was 12 inches in diameter and operated at a speed of 290 rpm. The airjet conveyor discharged air through 48 slots at velocities of approximately 7900 ft/min. Seed cotton was fed into the accelerating section from a conventional vacuum dropper on the unloading systems seed cotton separator. After passing over the air-pipe separator, the seed cotton was discharged into the hopper of an automatic feed control unit (FIG. 4). The total air requirement for this green boll separator was 3850 cfm. Seventeen percent of this air was needed in the accelerating section, and the remainder went into the air-pipes,.producing air-jet velocities of 6000 ft/min.

Early-season cotton containing 250 pounds of green bolls per bale was used in a test of the full-scale separae tor. The separator removed 244 pounds of green bolls per bale,.for an average efficiency of 98 percent. However, this test on the wider green boll separator re.- vealed a problemthat was not encountered in tests on the narrow, pilot model. It was found that the velocity of the air jets near the center of the pipes was adequate, but near the ends of the pipes the velocity was too low to convey the seedcotton properly, and some losses occurred at these points. The cause of this problem was traced to inadequacies in the method used to feed air into the ends of the pipes.

The method of feeding air into the pipes was changed to overcome this problem. The entire green boll sepa- 1 rator was redesigned so that air was supplied through an opening in the bottom of each pipe along its entire length (FIG. 5 and 6); This change produced uniform air jets the full length of the pipes. In addition to these changes, the green boll separator was also equipped with a recirculating air system. The intake of a 7.5 hp

fan was connected to the discharge hood of a seed cot-' ton collecting chamber. Seedcotton leaving the air green bolls was used to test this unit. The bells had,

moisture content ranging from -50 percent, instead of the normal 70 percent. Thus the green bolls used in this test were lighter in weight and more difficult to separate. Average green boll removal efficiencies. ranged from 53 to 61 percent, depending upon jet velocity.

Higher efficiencies were obtained with the lower jet velocities. As a result of using the light-weight green bolls,

the. efficiencies'obtained in this test were not as high as those of previous tests, and the. data showed greater variation. The amount of seed cotton iostwas not mea-' sured, but visual observation of the material being removed by'the air pipe separator indicated that the;

amount being lost was neg ligibl'e. In addition to removing green bolls, the separator removed some wet, im-

mature locks of cotton. This removal was considered beneficial since the locks were too wet to be ginned.

Additional tests were conducted to determine the capacity of the air pipe separator. Capacity is afunction of the spacing, velocity, and discharge angle of the air jets. An analysisof the data from these tests provided an indication that the air pipes should be spaced 9 to l 1 inches apart, center to center. A smaller spacing de creases green boll removal, and alarger spacing increases the loss of seed cotton. Air pipes spaced within the optimum range required air jet discharge angles of 12 to 20 above the horizontal to insure satisfactory conveying without excessive seed, cotton loss. With this arrangement, the air jet velocity required for dry seed cotton was 6500 to,7000 fpm; and for wet seed cotton,

approximately to 7500 fpm. Under these conditions the -inch-wide separator hassatisfactorily conveyed up to 27,800 pounds of, machine stripped cotton per hour. This quantity wasthe maximum that the Laboratorys unloading system could deliver to the green boll separator. In this test the separator was not fully loaded, and

it appeared that it could have satisfactorily handled a larger quantity of cotton.

The 5 to 7' hp required for operation of the air pipe green boll separator represents a sizable reduction A3) when compared with that required by the conventional separators (about l 5 hp).

Also, conventional green boll separators reduce the unloading capacityof suction unloading systems. The air pipe green boll separator is installed following the suction unloading system and has no effect upon its air flow characteristics.

The air pipe green boll separator removed the more dense materials from machine-stripped seed cotton and also removed many small particles. Because of its unique air separating characteristics, this separator offers possibilities for use in making separations of other agricultural productsthat can be classified on the basis of density orsize.

OBJECTIVES The main objective of this machine is in the use of in systemdesign. Another object of this invention is to reduce the energy required for accomplishing the desired separation of materials. Other objects and advantages of this invention will become apparent in the detailed description and drawings. c

GENERAL DESCRIPTION OFTHE'INVENTION This invention relates to a new type of machine for separation or classification of materials on the basis of different density and/0r aerodynamic transportation properties. More specifically, the machine. was developed for the separation of green bolls and other foreign materials from dry open cotton. Still more specifically, this machine was developed to accomplish the separation by use, of a series of nozzle assemblies which utilize.

compressed air exiting from each nozzle, through jet slots, the air then converging into a thinhorizontal cur-- tin of high velocity air which is directed to convey the less dense materials to theregion above'the next nozzle 1 in series.

- The nozzle assembly consists of two parts, an upper and a lower. Air is supplied to the lower half from an external source. The upperhalf consists of the nozzle head which contains a lower and an upper slot set in .at an angle, thereby controlling the angle at which the air jets discharge. Further control of the jet angle discharge can be achieved by adjusting the, nozzle assemblies using pivotpoints located above and below the 7 horizontal centerline of the nozzle assembly. These.

pivot points are attached to a mechanical adjusting 1ever. These nozzle asemblies are properly spaced in series.

The air pressure inside the nozzle is maintainedat the appropriate pressure to form jets at the nozzle slots which will provide an air stream at the appropriate velocity to convey the less dense materials into the region above the next nozzle in series but allow more dense materials to settle below the level necessary to enter the region above the next nozzle. The more dense ma terials usually impact on the back of the next nozzle losing their horizontal velocity, then fall vertically into a suitable collection means. Thus, efficient separation occurs.

DETAILED DESCRIPTION OF INVENTION In describing the preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. Machine dimensions, materials of construction, control devices, operating configurations and applications illustrated are typical only and all other more sophisticated equivalents are also intended.

FIG. 1, is an expanded view in perspective showing the various parts of the machine in relation to each other as typicallyassembled, with parts broken away to illustrate important details.

FIGS. 2a, 2b and 2c are side views of cross sections of the optional forms in which the air jet nozzles may be constructed.

FIG. 3, is a schematic diagram of the air separator indicating direction of flow and illustrating how seed cotton flows over air pipes and green bolls and trash falls between.

FIG. 4, is a schematic diagram of a typical air pipe separator installation illustrating separator in relation to the overall gin operation.

FIG. 5, is a front and side view of the details of the improved method of feeding air into air pipes in series.

FIG. 6, is an exploded isometric of one nozzle assembly showing upper nozzle portion in relation to lower air plenum portion and method of air feed through the entire horizontal nozzle length. It also shows the method of connection to the air plenum and outside air supply.

In the specific embodiment of the invention selected for illustration in the referenced drawing, FIG. 1 designates generally a machine for separating green bolls and other heavy, dense materials from dry open cotton. The materials to be separated are introduced into region 12 onto a short section of air jet conveyor 14 which is used to assure that the materials are accelerated to the proper velocity for air conveying horizontally across the air jet section 15 in'the region above nozzles 21 bounded by the sides 24 and 28 and top plate 34. The accelerating section 14 must discharge the cotton into the region above the first nozzle 2l at velocities between 1000 and 1400 feet per minute.

Compressed air from the plenum 16 within each nozzle 21 exits through jet slots 18 and 19, converging into a thin horizontal curtain of high velocity air which is directed to convey the less dense materials to the region above the next nozzle 21 in series. The air pressure inside plenum 16 is maintained at the appropriate pressure to form jets at slots 18 and 19 which will provide an air stream 20 at the appropriate velocity to convey the less dense materials into the region above the next nozzle 21 in series but allow more dense materials to settle below the level necessary to enter the region above the next nozzle. The more dense materials usually impact on the back of the next nozzle 21 losing their horizontal velocity, then fall vertically into a suitable collection means 22. The dense materials are gathered into a conveying means 23 by the collecting means 22, and conveyed to a disposal point 25.

Each succeeding stage nozzle of separation, nozzle to nozzle, performs identically as described except for a buildup of air volume flow in the region above the nozzles. Because of random position within the mass of material and interparticle drag, separation is not complete at any stage but the cumulative amount of separation increases at each stage until the less dense material (dry open cotton) is discharged from the machine at 38 in an air borne condition with velocity sufficient to carry it into the next unit of the system where it can be disposed of in any manner desired. However, empirical development data indicated that five stages produced. approximately 96 to 98 percent efficiency in green boll and trash removal. Limitations would result from the physical space available for the machine to occupy, the number of stages required for cumulative separation to reach the desired efficiency level, and cost. These would represent the controlling factors in determining the number of stages that could be utilized.

Air is supplied to this machine through connection to duct 39 which in turn is connected to plenums 16 and 37 by flexible conections between ports 40 and plenum openings 41. The air supply is regulated by controls external to this machine to provide the required pressure and volume at the inlet connection of duct 39. Balancing of the air supply within the machine is accomplished by adjustable baffles inserted in ports 40 of duct Variables which can be manipulated for control of the performance of the machine are: (l) spacing between nozzles 35, FIGS. 1 and 5, (2) the velocity of the air stream 20,'FIG. 2, (3) the direction of stream 20 with respect to the horizontal direction 17, FIG. 2. (4) the configuration of nozzles 21, FIG. 2 and (5) the size of the jets l8 and 19, FIG. 2.

The velocity ofjets l8 and 19 and the angle 17 of air stream 20 are the controlled variables. This is important in that without proper balancing of the variables the machine will not operate properly. The velocity of jets 18 and 19 is controlledby regulation of the air which is supplied to plenum 16. As previously stated this air supply is from an external source capable of either automatic or manual control.

The angle 17 of air stream 20 is controlled by moving the lower part of the nozzles 21 at pivot 26. The entire nozzle assembly rotates about pivoting means 27 which extend through housings 24 and 28 located on each side of the machine. The rotation of the nozzle is effected by an adjusting means consisting of a bar 29 located on each side of housings 23 and 28 and having a rounded and threaded end 60. End passes through bracket 31 and is adjustably held in place by threaded nuts 30 and 32. Pivots 26 pass through bar 29, under housings 24 and 28, and into'the vertical ends of nozzles 21 below the horizontal centerline of each nozzle.

Since bracket 31 is fixedly attached to housing 24 then the position of bar 29 may be adjustedby moving the nuts appropriately. This results in a change of the .verti cal axis of the nozzle assembly, and the desired resultant angleris achieved by this adjustment on each side of the machine.

The spacing 35 between the nozzles 21 is also adjustable. Proper settings for this spacing can be determined by the characteristics of the materials to be separated and by the velocity of the air in the jets and the angle at which the jets are operated..Optimum settings were determined empirically by trial and errormethods. For typical early season cotton as harvested containing green bolls with moisture contents ranging between 50 and 80 percent wet basis, the spacing 35 of 9 to l2 inches is considered optimum between nozzles 21.

' The velocity of the air jets l8 and 19 is considered optimum between 6500 and 7000 feet per minute. The .width of the opening in jets 18 and 19 is l/16 to /64- inch. The air stream from the converged jets discharges at an angle of to 20 above the horizontal. Air must a be supplied into plenum 16 in sufficient quantity to maintain a gauge pressure inside the plenum of 2.5 to 2.8 inches of water. i

There are many configurations which the nozzles 21 can take. However, for, purposes of illustration of the preferred'embodiments of this'invention, attention is V only a small round air plenum 16 which was attached to air supply ducts 39 on each end. Round slip connectors were used for attaching this nozzle to ducts 39 rather than the square ports 40, illustrated in FIG. 1, to allow rotation of the whole nozzle for adjusting discharge angle l7 of air stream20. Nozzle b, FIG. 2, is suitable for use in machines of limitedwidth because the small size of plenum 16 restricts the amount of air that can be supplied for forming jets l8 and 19. Specifically, the FIG. 2b embodiment is a pipe lying in a horizontal plane, the circumference of which is intersected by a solid acute angle member 31 which displaces the intersected portion thereof, the lower leg 52 of the acute angle, memberbeing curved to conformto the tangent of the pipe circumference at the pointof the lower intersection, and the upper intersected edge of the pipe circumference is straightened so that the upper straight leg 53 of the acute angle member forms a tangent with respect to the straightened upper intersected pipe circumference 59, and the acute angle members! off-set so that the pipe 50 circumference overlaps the acute angle member 51 at the upper and lower points of intersection and forms a 5/64 inch opening at the upper and lower points of intersection. The entire nozzle assembly is angled so that the jets l8 and 19 exhaust at a l2 angle above the horizontal and the air pipe is open on each end where it is attached to an air plenum (not shown). An external air supply (not shown) forces air in from both ends of pipe 50, thus forming the air plenum 16 and the jets 18 and 19. Nozzles shaped like FIG. 20 are suitable for use where it is desired to reduce the open space between nozzles to help prevent loss of the light materials with the dense materials being separated. FIG. 20 is an upper nozzle exhaust section comprising two vertically parallel sides,

one forward and one aft, the aft side 55 being longer than the forward side and bent forward in two places near the end so as to form substantially a 9 0 turn, the forward side 56 being bent forward in one place form- 7 ing substantially an obtuse'angle, the vertical sides affixed to two complimentary matching vertical ends (not shown), and anacute angle member 51 which .in-

tersects the forward andtaft leading edges of the said vertical sides, with the angle member being deflected inwardly on the ends to form openings atthe intersections of the angle member and the vertical sides, said opening 'coacting with an I external air supply (not shown) to plenum 16 thus forming jets l8 and 19. The

nozzle assembly is open on the bottom substantially the full width thereof, and an airtight means (not shown) of attaching the bottom of the nozzle assembly flange 57 to a nozzle assembly lower section, e.g., 16b in FIG..

6,'is provided. Nozzle shape FIG. 2a, is suitable for use where maximum open space between nozzles is desired l to achieve maximumseparation. Nozzle shapea, FIG.

2 is currently in use in the air jet seed cotton cleaner as illustrated in FIG. LThis nozzle comprises two vertical sides, the forward side 56 being longer than the aft side 55, the upper ends of said sides being bent to form an obtuse angle in the forward direction and the lower sides being fitted with a flange 57; Two parallel vertical ends (not shown) are designed and afixed to match the vertical sides 56 and 55 and are shorter in width than the vertical sides thus substantially forming with the sides aclosed vertical duct. At the bottom the duct is open and at the top is plate 51" positioned at an acute angle 17 between ends 58 and 59 and affixed by the vertical ends, thus producting openings which coact with a means of supplying air (not shown) and'plenum 16 to form jets I8 and 19. The nozzleof FIG. .2a..is

mounted by flange 57 on a nozzle assembly lower section, e.g., 16b of FIG. 6, by an airtight means (not shown). The orientation of the nozzle: and the nozzle assembly lower section may be changed by use of a pivoting means located on the vertical ends above the hor-' izontal centerline of the upper nozzle section and by use of an, adjusting means located on the vertical ends below the horizontal centerlines of the upper nozzle section, both of the foregoing features substantially as shown in FIG. 1. g

FIG. 6 is an exploded view drawing of one air jet nozzle assembly 21. The functioning air stream 20 (in FIG.

1 and FIG. 2) is formed by jet slots 18 and 19. Com-i pressed air for forming the jets is contained by plenum 16 (FIGS. 1 and .2), which is supplied from duct 39.

Plenum 16 is made up of upper and lower halves, 16a

and 16!). Upper. half 16a is a part of the jet head itself i and connects to lower half 16b. The compressed air is supplied to lower half 16b from duct 39 through openings 40 and 41. Openings 40and 41 are connected by a flexible boot (not shown) to allow movement of nozzle 21 to control the angle at which the .air jets discharge. Support of air jet nozzle assembly .21 and con-i trol of the discharge angle is accomplished through pivots attaching to each end of the nozzle at 43 and 44. Upper pivot point43 has attached a pivot boltwhich has a fixed location within the framework of the machine. Lower pivot point 44 has attached a pivot which connects to a bar which can be moved to rotate nozzle i 21 about point 43 for changing the discharge angle of the jets.

Duct 39 connects to the remaining air jet nozzles and the accelerating section through additional suitably located openings 40.

We claim:

1. An air jet nozzle assembly comprising a plurality of air jet nozzles having spaces therebetween, each nozzle comprising an air plenum having ends and both upper and lower longitudinal sections, as well as means for securing said sections together and means for securing said secured sections to said ends; means comprising two parallel slots in the upper section which communicate with said plenum for producing converging air jets; and means for pivoting said nozzles about an axis parallel to the slots.

2. The nozzle assembly of claim 1 further comprising an adjusting means located on the vertical ends below the horizontal centerline of each nozzle and pivoting means located on the vertical ends below the horizontal centerline of each nozzle.

3. The nozzle assembly of claim 2 wherein the adjusting means comprises a bar communicating with the ends of the nozzles by pivot means and having a round threaded end which passes through a stationary bracket, said threaded end held in place in said bracket by nuts screwed onto the threaded end and located on each side of the bracket.

4. An apparatus as defined in claim 2 wherein the pivoting means comprises: 7

a. a bolt attached to a tapped hole in the vertical ends of the nozzle, said tapped hole located above the horizontal centerline of the nozzle.

5. An apparatus as defined in claim 1 wherein the nozzle exhaust is set at an angle of 12 to 20 above the horizontal.

6. An apparatus as defined in claim 1 wherein the nozzle slots through which the air exhausts is a 16 gauge space.

7. An air jet nozzle used for separating and/or classifying materials on the basis of different density and/or aerodynamic transportation properties comprising:

a. a lower air plenum section substantially forming a vertical duct:

b. an upper nozzle section comprising:

1. two parallel vertical sides, the forward side being longer than the aft side, the upper ends of said sides being bent to form an obtuse angle in the forward direction and the lower ends being fitted with a flexible attachment means to attach to the lower section.

2. two parallel vertical ends designed and affixed to match the parallel vertical sides and shorter=in width than said vertical sides thus substantially forming the configuration of a closed vertical duct,

3. an open bottom substantially the horizontal width of the vertical duct,

4. a plate positioned and affixed by the saidvertical ends between the obtuse angularly bent ends of the forward and aft parallel vertical sides so as to form two parallel slots in the upper section,

5. a pivoting means located on the vertical ends above the horizontal centerline of the upper nozzle section,

6. an adjusting means located on the vertical ends below the horizontal centerline of the upper nozzle section,

c. means of affixing the upper noule section to the lower air plenum section, and

d. a means of supplying air to the nozzle assembly.

8. An air jet nozzle used for separating and/or classifying materials on the basis of different density and/or aerodynamic transportation properties comprising:

a. a pipe lying in a horizontal plane, the circumference of which is intersected by a solid acute angle member which displaces the intersected portion thereof, the lower leg of the acute angle member being curved to conform to the tangent of the pipe circumference at the point of the lower intersection, and the upper intersected edge of the pipe circumference is straightened so that the upper straight leg of the acute angle member forms a tangent with respect the straightened upper intersected pipe circumference, and the acute angle member off-set so that the pipe circumference overlaps the acute angle member at the upper and lower points of interseciton and forms a 5/64-inch slot at the upper and lower points of intersection, and the entire nozzle assembly being angled so that the air slots exhaust at a 12 angle above the horizontal, and the air pipe open on each end and attached to an air plenum thereby allowing air to be suppliedfrom both ends,

b. an external air supply to the air plenums.

9. An air jet nozzle assembly used for classifying materials on the basis of different density and/or aerodynamic transporation properties comprising:

a. an upper nozzle exhaust section comprising two vertically parallel sides, one forward and one aft, the aft side being longer than the forward side and bent forward in two places near the end so as to form substantially a turn, the forward side being bent forward in one place forming substantially an obtuse angle, the vertical sides affixed to two complimentary matching vertical ends, and an acute angle member which intersects the forward and aft leading edges of the said vertical sides, with the angle member being deflected inwardly on the ends to form slots at the intersections of the angle member and the vertical sides, and said nozzle open on the bottom substantially the full width thereof.

b. a means of attaching the bottom of the nozzle upper half to a nozzle lower half,

0. a lower half substantially forming a duct the full width of the nozzle upper half,

d. an external means of supplying air to the nozzle through the lower half,

e. a means of attaching the lower half to the external air supply. 

1. An air jet nozzle assembly comprising a plurality of air jet nozzles having spaces therebetween, each nozzle comprising an air plenum having ends and both upper and lower longitudinal sections, as well as means for securing said sections together and means for securing said secured sections to said ends; means comprising two parallel slots in the upper section which communicate with said plenum for producing converging air jets; and means for pivoting said nozzles about an axis parallel to the slots.
 2. The nozzle assembly of claim 1 further comprising an adjusting means located on the vertical ends below the horizontal centerline of each nozzle and pivoting means located on the vertical ends below the horizontal centerline of each nozzle.
 2. two parallel vertical ends designed and affixed to match the parallel vertical sides and shorter in width than said vertical sides thus substantially forming the configuration of a closed vertical duct,
 3. an open bottom substantially the horizontal width of the vertical duct,
 3. The nozzle assembly of claim 2 wherein the adjusting means comprises a bar communicating with the ends of the nozzles by pivot means and having a round threaded end which passes through a stationary bracket, said threaded end held in place in said bracket by nuts screwed onto the threaded end and located on each side of the bracket.
 4. An apparatus as defined in claim 2 wherein the pivoting means comprises: a. a bolt attached to a tapped hole in the vertical ends of the nozzle, said tapped hole located above the horizontal centerline of the nozzle.
 4. a plate positioned and affixed by the said vertical ends between the obtuse angularly bent ends of the forward and aft parallel vertical sides so as to form two parallel slots in the upper section,
 5. a pivoting means located on the vertical ends above the horizontal centerline of the upper nozzle section,
 5. An apparatus as defined in claim 1 wherein the nozzle exhaust is set at an angle of 12* to 20* above the horizontal.
 6. An apparatus as defined in claim 1 wherein the nozzle slots through which the air exhausts is a 16 gauge space.
 6. an adjusting means located on the vertical ends below the horizontal centerline of the upper nozzle section, c. means of affixing the upper nozzle section to the lower air plenum section, and d. a means of supplying air to the nozzle assembly.
 7. An air jet nozzle used for separating and/or classifying materials on the basis of different density and/or aerodynamic transportation properties comprising: a. a lower air plenum section substantially forming a vertical duct: b. an upper nozzle seCtion comprising:
 8. An air jet nozzle used for separating and/or classifying materials on the basis of different density and/or aerodynamic transportation properties comprising: a. a pipe lying in a horizontal plane, the circumference of which is intersected by a solid acute angle member which displaces the intersected portion thereof, the lower leg of the acute angle member being curved to conform to the tangent of the pipe circumference at the point of the lower intersection, and the upper intersected edge of the pipe circumference is straightened so that the upper straight leg of the acute angle member forms a tangent with respect the straightened upper intersected pipe circumference, and the acute angle member off-set so that the pipe circumference overlaps the acute angle member at the upper and lower points of interseciton and forms a 5/64-inch slot at the upper and lower points of intersection, and the entire nozzle assembly being angled so that the air slots exhaust at a 12* angle above the horizontal, and the air pipe open on each end and attached to an air plenum thereby allowing air to be supplied from both ends, b. an external air supply to the air plenums.
 9. An air jet nozzle assembly used for classifying materials on the basis of different density and/or aerodynamic transporation properties comprising: a. an upper nozzle exhaust section comprising two vertically parallel sides, one forward and one aft, the aft side being longer than the forward side and bent forward in two places near the end so as to form substantially a 90* turn, the forward side being bent forward in one place forming substantially an obtuse angle, the vertical sides affixed to two complimentary matching vertical ends, and an acute angle member which intersects the forward and aft leading edges of the said vertical sides, with the angle member being deflected inwardly on the ends to form slots at the intersections of the angle member and the vertical sides, and said nozzle open on the bottom substantially the full width thereof. b. a means of attaching the bottom of the nozzle upper half to a nozzle lower half, c. a lower half substantially forming a duct the full width of the nozzle upper half, d. an external means of supplying air to the nozzle through the lower half, e. a means of attaching the lower half to the external air supply. 